Near-infrared star map simulation for starlight refraction sensor based on ray tracing

Abstract

The application of starlight refraction navigation to spacecraft and space weapons is a significant development direction. Due to the huge cost of spacecraft experiments, the functional validation of this technology relies mainly on ground simulations. The existing refraction star-map simulation ignores the starlight refraction angle’s change with time and position, which cannot meet the engineering requirements. Based on the timed/saber dataset and geometric ray theory, this paper presents a ray tracing algorithm to calculate the starlight refraction angle in different propagation paths. Combined with the coordinate conversion and energy transfer, a near-infrared refraction star-map simulation method is proposed. An all-time star sensor is used for simulation, which works in the 900–1700 nm band and can suppress strong limb background. The experimental data verify the refraction angle and energy model of the proposed method. Through the comparison between the measured data and simulated star maps, the starlight refraction angle’s bias error of the proposed method is −0.05″, which is typically smaller than −3.30″ of the traditional method, and the average flux error is 11%. The evaluation and verification outcome support the proposed star-map simulation method and can provide technical support for the optimization design, capability estimation, and algorithm validation of the starlight refraction navigation.